On tonight's episode (May 31) of 'Duets,' the celebrity mentors and their amateur partners teamed up to sing some of the most famous duets in history. John Legend and his charge Bridget Carrington sang 'I Knew You Were Waiting (For Me),' popularized by Aretha Franklin and George Michael. Make it hard, why don'tcha guys! Singing a 'Retha song is like singing a Whitney Houston song. As in: it's hard!

In the pre-performance interview package, the Lege said he hoped for a rebound from last week, chalking that less-than-loved performance up to poor song choice.

Carrington brought sexy to the stage with her bright and shimmery blue and red mini dress, which she paired with a leather jacket, showing off some enviable legginess. She was most comfortable singing to Legend, but towards the end of the song, she made more eye contact with the audience and turned it up.

Her confidence was up, the song fit her voice and Legend almost stole the show from her. Almost. He let her "run" with it, by letting her do some vocal runs and Carrington blossomed at the end.

It was a strong finish, and as the amazing (and big-haired) Robin Thicke, who compared Carrington's blue and red dress to a "bag of Skittles," astutely pointed out, it's not how you start, but how you end. And she finished like a racehorse.

Legend and Carrington didn't falter, like the lyrics of the song state!